I have a 85' 120 johnson, I notice that the trim is going all the way down when I throttle up just a little. I understand that there is a relief valve. Please advise. I have to replace the trim motor because of the rust, could this be the problem?
The relief valve is on the left side midway on the motor bracket. There will be a hole, look inside and you should see a screw for a flat head screwdriver. Turn the screw clockwise and make sure its tight. If that doesn't work check fluid level. The rust on the motor is not your prob unless your leaking oil. This doesn't mean your pump isn't bad, but check that screw maybe youll have good luck with that.
The valve on the side is the Manual Release valve that allows yu to raise the engine manually in the event of a trim/tilt failure. You can also lower the engine with this valve(it just opens the fluid passage so the fluid can pass when lifting the engine by hand) When lowering the engine with the manual release valve it will only lower to full trim out position. The relief vavle is in the fluid resivoir. Your engine is going to full down trim. this will indicate either one of the valves in the manifold or blown trim cylinder seals.
